Intended for healthcare professionals

Rapid response to:


Risk of respiratory morbidity in term infants delivered by elective caesarean section: cohort study

BMJ 2008; 336 doi: (Published 10 January 2008) Cite this as: BMJ 2008;336:85

Rapid Response:

Improving Neonatal Outcome After Elective Caesarean Section at Term

In a large study Hansen et al concluded that there is a four-fold
increase in risk of respiratory distress in the newborn for those
delivered by elective caesarean section at 37 weeks gestation compared to
vaginal delivery, with a five-fold increase of serious respiratory
morbidity.(1) This is defined as a need for continuous oxygen
supplementation for 3 or more days, nasal CPAP or any period of mechanical
ventilation. This risk decreases with increasing gestational age but with
still a two-fold increase at 39 weeks gestation. There can be no doubt
from the extensive publications over the past 30 years that delivery by
elective caesarean section increases the risk of respiratory morbidity in
the neonate. In the absence of the stress of labour, there is no
catecholamine and cortisol release to stimulate lung fluid absorption and
surfactant production, resulting in a delay in adaptation to birth
particularly with the more immature lungs of those less than 40 weeks
gestation, leading to respiratory distress.

Whenever an elective caesarean section is planned it is important
that these risks are discussed with the mother. These can be reduced by
planning the section for 39 weeks gestation, aware that an emergency
section may be necessary if labour commences before this time. From 39
weeks gestation onwards the absolute risk of unexplained stillbirth with
women who had a previous caesarean delivery are increased and calculated
at 1.06/1000.(2)

In a large randomised controlled trial we demonstrated that the
recognised benefits of the widely used antenatal betamethasone for preterm
deliveries, extended to term babies delivered by elective caesarean
section, halving the incidence of respiratory distress at 37-39 weeks
gestation.(3) Hansen et al make reference to this but raise the sceptre
of safety with reference to the editorial accompanying our Paper.(4) This
editorial did not present the published data in a balanced way, totally
contrary to the meta-analysis undertaken for the Cochrane review and the
Royal College of Obstetricians and Gynaecologists guidelines on the safety
of a single course of antenatal betamethasone.(5-8) With many
publications up to 31 years follow-up, it is safe to conclude there is no
evidence of long-term effect of a single course. (6-9)

Clinical management can be influenced by unsubstantiated statements
which are published unless the original data is checked. With reference
to our study , the assertion by Hutchon (rapid response above) that
morbidity, cost and separation of mother and baby were not significantly
reduced is incorrect and based on guesswork.. In the betamethasone group
we report 11 babies admitted with respiratory distress, 15 for other
reasons, a total of 26 and in the control group, 24 with respiratory
distress, 8 other reasons, a total of 32 admissions. Our study was not
powered to make conclusions about admissions other than for respiratory
distress. However revisiting the data, considering admissions for all
causes, babies in the betamethasone group were admitted for a total of 84
days which includes 35 days for respiratory causes 5 of which were
intensive care. Babies in the control group were admitted for a total of
167 days, 129 of these with respiratory distress including 65 days
intensive care . The total number of admission days to the neonatal unit
were reduced by 50% confirming reduced morbidity , cost and separation of
mother and baby for those in the betamethasone group.

Despite the volume of publications demonstrating the benefits of
antenatal betamethasone in reducing respiratory distress, Hutchon proposes
that there is an opportunity to prevent respiratory problems after
caesarean section with delayed clamping of the cord. This again is
speculation and not supported by evidence, with a misleading reference to
the Cochrane Review and a “number of studies”.(10) The Cochrane Review
concluded that there was evidence of reduced need in the preterm infant
for blood transfusions with less intraventricular haemorrhage with delayed
cord clamping, and insufficient evidence for a reliable conclusion about
any respiratory effect.

There is sufficient evidence from follow-up studies of no adverse
outcome from a single course of antenatal betamethasone to recommend that
if an elective caesarean section has to be undertaken before 39 weeks
gestation, that the benefits of a single course of antenatal betamethasone
48 hours before delivery should be discussed with mother when planning the
delivery. The opportunity of reducing the adverse consequences of serious
respiratory disease in those delivered by elective caesarean section
before 39 weeks gestation should not be delayed a further 10 years through
unsubstantiated assertions and a misleading editorial that gets repeatedly


1.Hansen AK, Wisberg K, Uldebjog N, Henriksen TB. Risk of
respiratory morbidity in term infants delivered by elective caesarean
section; cohort study. BMJ 2008; 336; 85-87.

2.Smith GS, Pell JP, Dobbie R . Caesarean section and risk of
unexplained stillbirths in subsequent pregnancy. Lancet 2003; 362: 1779-

3.Stutchfield PR, Whittaker R, Russell I. Antenatal betamethasone
and incidence of neonatal respiratory distress after elective caesarean
section; pragmatic randomised trial. BMJ 2005; 331: 662-4

4.Steer PJ. Giving steroids before elective caesarean section. BMJ
2005; 331: 645-6

5.Hey E. The fallibility of experts.

6.Crowley P,Roberts D, Dalziel S,Shaw BNJ. Antenatal corticosteroids
to accelerate fetal lung maturation for women at risk of preterm birth.
Cochrane Database of Systematic Reviews 2003;4; CD004454

7.Antenatal corticosteroids to prevent respiratory distress syndrome.

RCOG 2004, Guideline no. 7

8.Roberts D,Dalziel S . Antenatal corticosteroids for accelerating
fetal lung maturation

for women at risk of preterm birth . Cochrane Database of Systematic
Reviews 2006, issue 3 reprinted 2008 Art

9.Dalziel SR, Lim VK, Lambert A, McCarthy D, Paraq V. Antenatal
exposure to betamethasone: psychological functioning and health related
quality of life 31 years after inclusion in randomised controlled trials.
BMJ 2005; 331: 665-668

10.Rabe H, Reynolds G, Diaz-Rossello J. Early versus delayed
umbilical cord clamping in preterm infants. Cochrane Database of Systemic
Reviews 2004, issue 4, Art No: CD 003248. DOI: 10.1002/14651858. CD
003248. pub 2 republished 2008 issue 1

Competing interests:
None declared

Competing interests: No competing interests

07 February 2008
Peter Roy Stutchfield
Consultant Paediatrician
Rhiannon Whitaker
Conwy and Denbighshire NHS Trust , Glan Clwyd Hospital,Rhyl,Denbighshire LL18 5UJ